Agree with water, coffee creamer, sunscreen ( takes up too much space in luggage! ) and I will probably be made fun of for this one, BUT here ya go anyway
We always purchase or order soft toilet paper!!! I HATE the cheap stuff in hotel rooms. For a night here and there, okay, but for a week, no way. My kids always ask if I ordered the soft stuff we keep at home
My cart currently has 20+ items, so I could tell you more, but some of it is restocking our Owner's Locker that we leave down there so may not be beneficial.